Tag: Ubuntu

install ShadowSocks client in Ubuntu 18.04
ShadowSocks client is part of shadowsocks package. This include both client and server. If you are looking to install server, see Install ShadowSocks server on Debian 10

To install ShadowSocks, run
```
apt install -y shadowsocks
```
ShadowSocks client is called sslocal, get installed in /usr/bin/sslocal.

On Ubuntu, no start up script provided with this package, so you need to create one or manually run sslocal when required.

Create a service file
```
vi /lib/systemd/system/[email protected]
```
Add following content
```
[Unit]
Description=Shadowsocks client mode service
Documentation=man:sslocal(1)
After=network-online.target

[Service]
Type=simple
User=nobody
Group=nogroup
ExecStart=/usr/bin/sslocal -q -c /etc/shadowsocks/%i.json
Restart=on-failure
RestartSec=30

[Install]
WantedBy=multi-user.target
```
Now we need to create a configuration file with your ShadowSocks server IP and password.
```
mkdir /etc/shadowsocks/
vi /etc/shadowsocks/local.json
```
Add following content
```
{
    "server":"YOUR_SERVER_IP",
    "server_port":8044,
    "local_address": "127.0.0.1",
    "local_port":8044,
    "password":"PASSWORD",
    "timeout":300,
    "method":"aes-256-cfb",
    "fast_open": false,
    "workers": 1,
    "prefer_ipv6": false
}
```
“server” = IP of the server where you installled ShadowSocks server.
“server_port” = Port used by ShadowSocks server
“password” = ShadowSocks server password.

local_port can be anything you like.

Enable shadowsocks service
```
systemctl enable shadowsocks-local@local
```
To start
```
systemctl start shadowsocks-local@local
```
To see status
```
systemctl status shadowsocks-local@local
```
Now you can configure your browser or other sock proxy supported application using 127.0.0.1:8044. Here is how to configure firefox
August 26, 2019
Setting up MineCraft Server in Ubuntu
To setup MineCraft server on Ubuntu, first you need to install Java.
```
apt install openjdk-8-jre -y
```
Create a user to run minecraft
```
useradd -m --shell /bin/bash minecraft
```
You can set a password if you want direct SSH login to this user or login as root, then “su – minecraft”.
```
passwd minecraft
```
Login as user minecraft with SSH or “su”.

Download minecraft server .jar file from

https://www.minecraft.net/en-us/download/server/

At the time of writing, i downloaded
```
wget https://launcher.mojang.com/v1/objects/3dc3d84a581f14691199cf6831b71ed1296a9fdf/server.jar
```
Don’t use above link as it can get older, always go to minecraft site and get new link, so you get latest minecraft server jar file.

You can start minecraft server with command
```
java -Xmx1024M -Xms1024M -jar server.jar nogui
```
First time when you run, it exit with some error related to EULA.

You need to edit file
```
vi eula.txt
```
Set
```
eula=true
```
Now minecraft will run. You can create a run.sh file with following command for starting minecrat easily.
```
vi ~/start.sh
```
Paste following content
```
#!/bin/bash

java -Xmx1024M -Xms1024M -jar server.jar nogui
```
To make the file executable, chmod it 755
```
chmod 755 ~/start.sh
```
When you start minecraft from terminal/ssh, it get closed when you disconnect. To keep minecraft server running after you disconnect, use tmux or screen.
August 20, 2019
networking
On Ubuntu 19.04, networking service is provided by package ifupdown
```
apt install -y ifupdown
```
By default this package is not installed. So if you add network interface configuration in /etc/network/interfaces, it won’t work.

Ubuntu 18.04 + use netplan instead of ifupdown/networking service to configure network interfaces.

Linux KVM Bridge network on Ubuntu

Configure OVH Bridge Network from command line
August 18, 2019

Ubuntu Configure systemd-resolved

Latest Ubuntu/Debian use systemd-resolved for DNS resolution. On a fresh Ubuntu 19.04 install DNS failed to resolve.

root@ubuntu19:/# ping serverok.in
ping: serverok.in: Temporary failure in name resolution
root@ubuntu19:/#

To fix this, create file

mkdir /etc/systemd/resolved.conf.d/
vi /etc/systemd/resolved.conf.d/dns_servers.conf

Add content

[Resolve]
DNS=8.8.8.8 1.1.1.1

Restart systemd-resolved

systemctl restart systemd-resolved

You can find systemd-resolvd status with command

resolvectl status
systemd-resolve --status

To resolve a domain, use

resolvectl query serverok.in

August 18, 2019

Ubuntu remove SSH welcome message
When you login to an Ubuntu server using SSH, you get welcome message like

On most Linux systems, this is generated by /etc/motd. On Ubuntu, MOTD (message of the day) generated dynamically with some scripts. I don’t want to see all the marketing message from Ubuntu everyday.

To disable MOTD on Ubuntu, just delete the scripts from /etc/update-motd.d/
```
rm -f /etc/update-motd.d/*
```
If you want a differnt motd, you can put a shell script in this folder.

Method 2

Another way to disable motd is by disabling pam_motd.so module.

Edit files
```
/etc/pam.d/login
/etc/pam.d/sshd
```
Comment out the lines related to pam_motd.so
```
session    optional     pam_motd.so  motd=/run/motd.dynamic
session    optional     pam_motd.so noupdate
```
August 17, 2019
nmtui
nmtui allow you to configure network interface if you are using network manager.

On Debian/Ubuntu, it is part of network-manager package
```
apt install network-manager
```
August 16, 2019

Install Linux Kernel 5.0 on Ubuntu 18.04 LTS

Ubuntu 18.04 was released with Linux kernel 4.15

root@DUS-147022:~# hostnamectl
   Static hostname: DUS-147022.op-net.com
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: 1fcb383ac03e4299a3b994dca4c51a10
           Boot ID: 66d616e9b11145c38387d71f9c48a4bd
  Operating System: Ubuntu 18.04.3 LTS
            Kernel: Linux 4.15.0-58-generic
      Architecture: x86-64
root@DUS-147022:~#

On 8 Aug 2019, Cannonical released Ubuntu 18.04.3 LTS with Linux Kernel 5.0.

If you are using older Ubuntu 18.04 point release, you won’t get newer kernel when you do software upgrade.

To get newer Linux kernal installed, you need to install Hardware enablement (HWE) stack, this provide newer kernel that provide support for latest hardware.

To install Hardware enablement (HWE) stack, run

apt install linux-generic-hwe-18.04

if this is Desktop computer, you may need to run

apt install linux-generic-hwe-18.04 xserver-xorg-hwe-18.04

after installing, reboot

reboot

after reboot, you will see latest Linux Kernel.

boby@sok-01:~$ hostnamectl
   Static hostname: sok-01
         Icon name: computer-desktop
           Chassis: desktop
        Machine ID: 70486772aac1410c9a8031851ab60a0d
           Boot ID: 6c946c08f95d4c6b883e6790ab83e728
  Operating System: Ubuntu 18.04.3 LTS
            Kernel: Linux 5.0.0-25-generic
      Architecture: x86-64
boby@sok-01:~$

August 16, 2019

Remote Desktop
Remote Desktop Software

https://guacamole.apache.org
Google Chome Remote Desktop
https://rustdesk.com – Free Open source teamviewer alternative.

Enable Remote Desktop
See vnc
August 7, 2019
Enable Remote Desktop in Ubuntu 18.04

To enable remote desktop on Ubuntu 18.04 (works with newer Ubuntu versions), go to settings.

Click on Sharing

Click on ON/OFF button on title bar to enable Desktop Sharing. Once enabled, click on “Screen Sharing” to See Desktop sharing option, you need to enable it for network connection.

Ubuntu use vino package to allow remote desktop over VNC.

See Ubuntu, VNC, remote desktop

July 27, 2019
Monitor Apache site traffic with Apachetop
apachetop is a command line tool like top, that shows traffic on a web site. It used apache access log to show th stats. This will be useful to monitor a web sites traffic in real time.
```
cd /usr/local/src
wget https://github.com/HostOnNet/apachetop/archive/master.zip
unzip master.zip
cd apachetop-master
./configure --with-logfile=/var/log/httpd/access_log
make
make install
```
If you need to set path to apache log file, configure with
```
./configure --with-logfile=/path/to/apache/log/file.log
```
On CentOS
```
yum install apachetop
```
On Ubuntu/Debian
```
apt install apachetop
```
Running apachetop with custom log file location
```
apachetop -f /path/to/apache/log/file.log
```
July 20, 2019
Install x11vnc on Ubuntu
To install x11vnc on Debian/Ubuntu, run
```
apt install -y x11vnc
```
To start vnc server, run
```
x11vnc -display :0
```
By default, there will be no password. To set password, run
```
x11vnc -storepasswd
```
To start x11vnc server with password, run
```
x11vnc -rfbauth ~/.vnc/passwd
```
July 17, 2019

Set default PHP version in Ubuntu

To select default PHP version in Ubuntu, run

update-alternatives --config  php

This will show a menu, you can select the default php version

root@server:/usr/bin# update-alternatives --config  php
There are 2 choices for the alternative php (providing /usr/bin/php).

  Selection    Path             Priority   Status
------------------------------------------------------------
* 0            /usr/bin/php7.0   70        auto mode
  1            /usr/bin/php5.6   56        manual mode
  2            /usr/bin/php7.0   70        manual mode

Press  to keep the current choice[*], or type selection number: 1
update-alternatives: using /usr/bin/php5.6 to provide /usr/bin/php (php) in manual mode
root@server:/usr/bin#

After setting PHP 5.6 as default PHP version, you will see

root@server:~# php -v
PHP 5.6.40-8+0~20190531120521.15+stretch~1.gbpa77d1d (cli) 
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies
root@server:~#

June 18, 2019

Tag: Ubuntu

Method 2

Remote Desktop Software

Enable Remote Desktop

On CentOS

On Ubuntu/Debian

Running apachetop with custom log file location